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llvm-mirror/lib/Linker/LinkModules.cpp
Bill Wendling b5f433b14d It's possible for two types, which are isomorphic, to be added to the 
destination module, but one of them isn't used in the destination module. If
another module comes along and the uses the unused type, there could be type
conflicts when the modules are finally linked together. (This happened when
building LLVM.)

The test that was reduced is:

Module A:

%Z = type { %A }
%A = type { %B.1, [7 x x86_fp80] }
%B.1 = type { %C }
%C = type { i8* }

declare void @func_x(%C*, i64, i64)
declare void @func_z(%Z* nocapture)

Module B:

%B = type { %C.1 }
%C.1 = type { i8* }
%A.2 = type { %B.3, [5 x x86_fp80] }
%B.3 = type { %C.1 }

define void @func_z() {
  %x = alloca %A.2, align 16
  %y = getelementptr inbounds %A.2* %x, i64 0, i32 0, i32 0
  call void @func_x(%C.1* %y, i64 37, i64 927) nounwind
  ret void
}

declare void @func_x(%C.1*, i64, i64)
declare void @func_y(%B* nocapture)

(Unfortunately, this test doesn't fail under llvm-link, only during an LTO
linking.) The '%C' and '%C.1' clash. The destination module gets the '%C'
declaration. When merging Module B, it looks at the '%C.1' subtype of the '%B'
structure. It adds that in, because that's cool. And when '%B.3' is processed,
it uses the '%C.1'. But the '%B' has used '%C' and we prefer to use '%C'. So the
'@func_x' type is changed to 'void (%C*, i64, i64)', but the type of '%x' in
'@func_z' remains '%A.2'. The GEP resolves to a '%C.1', which conflicts with the
'@func_x' signature.

We can resolve this situation by making sure that the type is used in the
destination before saying that it should be used in the module being merged in.

With this fix, LLVM and Clang both compile under LTO.
<rdar://problem/10913281>

llvm-svn: 153351
2012-03-23 23:17:38 +00:00

1338 lines
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//===- lib/Linker/LinkModules.cpp - Module Linker Implementation ----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the LLVM module linker.
//
//===----------------------------------------------------------------------===//
#include "llvm/Linker.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Instructions.h"
#include "llvm/Module.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
#include <cctype>
using namespace llvm;
//===----------------------------------------------------------------------===//
// TypeMap implementation.
//===----------------------------------------------------------------------===//
namespace {
class TypeMapTy : public ValueMapTypeRemapper {
/// MappedTypes - This is a mapping from a source type to a destination type
/// to use.
DenseMap<Type*, Type*> MappedTypes;
/// SpeculativeTypes - When checking to see if two subgraphs are isomorphic,
/// we speculatively add types to MappedTypes, but keep track of them here in
/// case we need to roll back.
SmallVector<Type*, 16> SpeculativeTypes;
/// SrcDefinitionsToResolve - This is a list of non-opaque structs in the
/// source module that are mapped to an opaque struct in the destination
/// module.
SmallVector<StructType*, 16> SrcDefinitionsToResolve;
/// DstResolvedOpaqueTypes - This is the set of opaque types in the
/// destination modules who are getting a body from the source module.
SmallPtrSet<StructType*, 16> DstResolvedOpaqueTypes;
public:
/// addTypeMapping - Indicate that the specified type in the destination
/// module is conceptually equivalent to the specified type in the source
/// module.
void addTypeMapping(Type *DstTy, Type *SrcTy);
/// linkDefinedTypeBodies - Produce a body for an opaque type in the dest
/// module from a type definition in the source module.
void linkDefinedTypeBodies();
/// get - Return the mapped type to use for the specified input type from the
/// source module.
Type *get(Type *SrcTy);
FunctionType *get(FunctionType *T) {return cast<FunctionType>(get((Type*)T));}
/// dump - Dump out the type map for debugging purposes.
void dump() const {
for (DenseMap<Type*, Type*>::const_iterator
I = MappedTypes.begin(), E = MappedTypes.end(); I != E; ++I) {
dbgs() << "TypeMap: ";
I->first->dump();
dbgs() << " => ";
I->second->dump();
dbgs() << '\n';
}
}
private:
Type *getImpl(Type *T);
/// remapType - Implement the ValueMapTypeRemapper interface.
Type *remapType(Type *SrcTy) {
return get(SrcTy);
}
bool areTypesIsomorphic(Type *DstTy, Type *SrcTy);
};
}
void TypeMapTy::addTypeMapping(Type *DstTy, Type *SrcTy) {
Type *&Entry = MappedTypes[SrcTy];
if (Entry) return;
if (DstTy == SrcTy) {
Entry = DstTy;
return;
}
// Check to see if these types are recursively isomorphic and establish a
// mapping between them if so.
if (!areTypesIsomorphic(DstTy, SrcTy)) {
// Oops, they aren't isomorphic. Just discard this request by rolling out
// any speculative mappings we've established.
for (unsigned i = 0, e = SpeculativeTypes.size(); i != e; ++i)
MappedTypes.erase(SpeculativeTypes[i]);
}
SpeculativeTypes.clear();
}
/// areTypesIsomorphic - Recursively walk this pair of types, returning true
/// if they are isomorphic, false if they are not.
bool TypeMapTy::areTypesIsomorphic(Type *DstTy, Type *SrcTy) {
// Two types with differing kinds are clearly not isomorphic.
if (DstTy->getTypeID() != SrcTy->getTypeID()) return false;
// If we have an entry in the MappedTypes table, then we have our answer.
Type *&Entry = MappedTypes[SrcTy];
if (Entry)
return Entry == DstTy;
// Two identical types are clearly isomorphic. Remember this
// non-speculatively.
if (DstTy == SrcTy) {
Entry = DstTy;
return true;
}
// Okay, we have two types with identical kinds that we haven't seen before.
// If this is an opaque struct type, special case it.
if (StructType *SSTy = dyn_cast<StructType>(SrcTy)) {
// Mapping an opaque type to any struct, just keep the dest struct.
if (SSTy->isOpaque()) {
Entry = DstTy;
SpeculativeTypes.push_back(SrcTy);
return true;
}
// Mapping a non-opaque source type to an opaque dest. If this is the first
// type that we're mapping onto this destination type then we succeed. Keep
// the dest, but fill it in later. This doesn't need to be speculative. If
// this is the second (different) type that we're trying to map onto the
// same opaque type then we fail.
if (cast<StructType>(DstTy)->isOpaque()) {
// We can only map one source type onto the opaque destination type.
if (!DstResolvedOpaqueTypes.insert(cast<StructType>(DstTy)))
return false;
SrcDefinitionsToResolve.push_back(SSTy);
Entry = DstTy;
return true;
}
}
// If the number of subtypes disagree between the two types, then we fail.
if (SrcTy->getNumContainedTypes() != DstTy->getNumContainedTypes())
return false;
// Fail if any of the extra properties (e.g. array size) of the type disagree.
if (isa<IntegerType>(DstTy))
return false; // bitwidth disagrees.
if (PointerType *PT = dyn_cast<PointerType>(DstTy)) {
if (PT->getAddressSpace() != cast<PointerType>(SrcTy)->getAddressSpace())
return false;
} else if (FunctionType *FT = dyn_cast<FunctionType>(DstTy)) {
if (FT->isVarArg() != cast<FunctionType>(SrcTy)->isVarArg())
return false;
} else if (StructType *DSTy = dyn_cast<StructType>(DstTy)) {
StructType *SSTy = cast<StructType>(SrcTy);
if (DSTy->isLiteral() != SSTy->isLiteral() ||
DSTy->isPacked() != SSTy->isPacked())
return false;
} else if (ArrayType *DATy = dyn_cast<ArrayType>(DstTy)) {
if (DATy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements())
return false;
} else if (VectorType *DVTy = dyn_cast<VectorType>(DstTy)) {
if (DVTy->getNumElements() != cast<ArrayType>(SrcTy)->getNumElements())
return false;
}
// Otherwise, we speculate that these two types will line up and recursively
// check the subelements.
Entry = DstTy;
SpeculativeTypes.push_back(SrcTy);
for (unsigned i = 0, e = SrcTy->getNumContainedTypes(); i != e; ++i)
if (!areTypesIsomorphic(DstTy->getContainedType(i),
SrcTy->getContainedType(i)))
return false;
// If everything seems to have lined up, then everything is great.
return true;
}
/// linkDefinedTypeBodies - Produce a body for an opaque type in the dest
/// module from a type definition in the source module.
void TypeMapTy::linkDefinedTypeBodies() {
SmallVector<Type*, 16> Elements;
SmallString<16> TmpName;
// Note that processing entries in this loop (calling 'get') can add new
// entries to the SrcDefinitionsToResolve vector.
while (!SrcDefinitionsToResolve.empty()) {
StructType *SrcSTy = SrcDefinitionsToResolve.pop_back_val();
StructType *DstSTy = cast<StructType>(MappedTypes[SrcSTy]);
// TypeMap is a many-to-one mapping, if there were multiple types that
// provide a body for DstSTy then previous iterations of this loop may have
// already handled it. Just ignore this case.
if (!DstSTy->isOpaque()) continue;
assert(!SrcSTy->isOpaque() && "Not resolving a definition?");
// Map the body of the source type over to a new body for the dest type.
Elements.resize(SrcSTy->getNumElements());
for (unsigned i = 0, e = Elements.size(); i != e; ++i)
Elements[i] = getImpl(SrcSTy->getElementType(i));
DstSTy->setBody(Elements, SrcSTy->isPacked());
// If DstSTy has no name or has a longer name than STy, then viciously steal
// STy's name.
if (!SrcSTy->hasName()) continue;
StringRef SrcName = SrcSTy->getName();
if (!DstSTy->hasName() || DstSTy->getName().size() > SrcName.size()) {
TmpName.insert(TmpName.end(), SrcName.begin(), SrcName.end());
SrcSTy->setName("");
DstSTy->setName(TmpName.str());
TmpName.clear();
}
}
DstResolvedOpaqueTypes.clear();
}
/// get - Return the mapped type to use for the specified input type from the
/// source module.
Type *TypeMapTy::get(Type *Ty) {
Type *Result = getImpl(Ty);
// If this caused a reference to any struct type, resolve it before returning.
if (!SrcDefinitionsToResolve.empty())
linkDefinedTypeBodies();
return Result;
}
/// getImpl - This is the recursive version of get().
Type *TypeMapTy::getImpl(Type *Ty) {
// If we already have an entry for this type, return it.
Type **Entry = &MappedTypes[Ty];
if (*Entry) return *Entry;
// If this is not a named struct type, then just map all of the elements and
// then rebuild the type from inside out.
if (!isa<StructType>(Ty) || cast<StructType>(Ty)->isLiteral()) {
// If there are no element types to map, then the type is itself. This is
// true for the anonymous {} struct, things like 'float', integers, etc.
if (Ty->getNumContainedTypes() == 0)
return *Entry = Ty;
// Remap all of the elements, keeping track of whether any of them change.
bool AnyChange = false;
SmallVector<Type*, 4> ElementTypes;
ElementTypes.resize(Ty->getNumContainedTypes());
for (unsigned i = 0, e = Ty->getNumContainedTypes(); i != e; ++i) {
ElementTypes[i] = getImpl(Ty->getContainedType(i));
AnyChange |= ElementTypes[i] != Ty->getContainedType(i);
}
// If we found our type while recursively processing stuff, just use it.
Entry = &MappedTypes[Ty];
if (*Entry) return *Entry;
// If all of the element types mapped directly over, then the type is usable
// as-is.
if (!AnyChange)
return *Entry = Ty;
// Otherwise, rebuild a modified type.
switch (Ty->getTypeID()) {
default: llvm_unreachable("unknown derived type to remap");
case Type::ArrayTyID:
return *Entry = ArrayType::get(ElementTypes[0],
cast<ArrayType>(Ty)->getNumElements());
case Type::VectorTyID:
return *Entry = VectorType::get(ElementTypes[0],
cast<VectorType>(Ty)->getNumElements());
case Type::PointerTyID:
return *Entry = PointerType::get(ElementTypes[0],
cast<PointerType>(Ty)->getAddressSpace());
case Type::FunctionTyID:
return *Entry = FunctionType::get(ElementTypes[0],
makeArrayRef(ElementTypes).slice(1),
cast<FunctionType>(Ty)->isVarArg());
case Type::StructTyID:
// Note that this is only reached for anonymous structs.
return *Entry = StructType::get(Ty->getContext(), ElementTypes,
cast<StructType>(Ty)->isPacked());
}
}
// Otherwise, this is an unmapped named struct. If the struct can be directly
// mapped over, just use it as-is. This happens in a case when the linked-in
// module has something like:
// %T = type {%T*, i32}
// @GV = global %T* null
// where T does not exist at all in the destination module.
//
// The other case we watch for is when the type is not in the destination
// module, but that it has to be rebuilt because it refers to something that
// is already mapped. For example, if the destination module has:
// %A = type { i32 }
// and the source module has something like
// %A' = type { i32 }
// %B = type { %A'* }
// @GV = global %B* null
// then we want to create a new type: "%B = type { %A*}" and have it take the
// pristine "%B" name from the source module.
//
// To determine which case this is, we have to recursively walk the type graph
// speculating that we'll be able to reuse it unmodified. Only if this is
// safe would we map the entire thing over. Because this is an optimization,
// and is not required for the prettiness of the linked module, we just skip
// it and always rebuild a type here.
StructType *STy = cast<StructType>(Ty);
// If the type is opaque, we can just use it directly.
if (STy->isOpaque())
return *Entry = STy;
// Otherwise we create a new type and resolve its body later. This will be
// resolved by the top level of get().
SrcDefinitionsToResolve.push_back(STy);
StructType *DTy = StructType::create(STy->getContext());
DstResolvedOpaqueTypes.insert(DTy);
return *Entry = DTy;
}
//===----------------------------------------------------------------------===//
// ModuleLinker implementation.
//===----------------------------------------------------------------------===//
namespace {
/// ModuleLinker - This is an implementation class for the LinkModules
/// function, which is the entrypoint for this file.
class ModuleLinker {
Module *DstM, *SrcM;
TypeMapTy TypeMap;
/// ValueMap - Mapping of values from what they used to be in Src, to what
/// they are now in DstM. ValueToValueMapTy is a ValueMap, which involves
/// some overhead due to the use of Value handles which the Linker doesn't
/// actually need, but this allows us to reuse the ValueMapper code.
ValueToValueMapTy ValueMap;
struct AppendingVarInfo {
GlobalVariable *NewGV; // New aggregate global in dest module.
Constant *DstInit; // Old initializer from dest module.
Constant *SrcInit; // Old initializer from src module.
};
std::vector<AppendingVarInfo> AppendingVars;
unsigned Mode; // Mode to treat source module.
// Set of items not to link in from source.
SmallPtrSet<const Value*, 16> DoNotLinkFromSource;
// Vector of functions to lazily link in.
std::vector<Function*> LazilyLinkFunctions;
public:
std::string ErrorMsg;
ModuleLinker(Module *dstM, Module *srcM, unsigned mode)
: DstM(dstM), SrcM(srcM), Mode(mode) { }
bool run();
private:
/// emitError - Helper method for setting a message and returning an error
/// code.
bool emitError(const Twine &Message) {
ErrorMsg = Message.str();
return true;
}
/// getLinkageResult - This analyzes the two global values and determines
/// what the result will look like in the destination module.
bool getLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
GlobalValue::LinkageTypes &LT,
GlobalValue::VisibilityTypes &Vis,
bool &LinkFromSrc);
/// getLinkedToGlobal - Given a global in the source module, return the
/// global in the destination module that is being linked to, if any.
GlobalValue *getLinkedToGlobal(GlobalValue *SrcGV) {
// If the source has no name it can't link. If it has local linkage,
// there is no name match-up going on.
if (!SrcGV->hasName() || SrcGV->hasLocalLinkage())
return 0;
// Otherwise see if we have a match in the destination module's symtab.
GlobalValue *DGV = DstM->getNamedValue(SrcGV->getName());
if (DGV == 0) return 0;
// If we found a global with the same name in the dest module, but it has
// internal linkage, we are really not doing any linkage here.
if (DGV->hasLocalLinkage())
return 0;
// Otherwise, we do in fact link to the destination global.
return DGV;
}
void computeTypeMapping();
bool categorizeModuleFlagNodes(const NamedMDNode *ModFlags,
DenseMap<MDString*, MDNode*> &ErrorNode,
DenseMap<MDString*, MDNode*> &WarningNode,
DenseMap<MDString*, MDNode*> &OverrideNode,
DenseMap<MDString*,
SmallSetVector<MDNode*, 8> > &RequireNodes,
SmallSetVector<MDString*, 16> &SeenIDs);
bool linkAppendingVarProto(GlobalVariable *DstGV, GlobalVariable *SrcGV);
bool linkGlobalProto(GlobalVariable *SrcGV);
bool linkFunctionProto(Function *SrcF);
bool linkAliasProto(GlobalAlias *SrcA);
bool linkModuleFlagsMetadata();
void linkAppendingVarInit(const AppendingVarInfo &AVI);
void linkGlobalInits();
void linkFunctionBody(Function *Dst, Function *Src);
void linkAliasBodies();
void linkNamedMDNodes();
};
}
/// forceRenaming - The LLVM SymbolTable class autorenames globals that conflict
/// in the symbol table. This is good for all clients except for us. Go
/// through the trouble to force this back.
static void forceRenaming(GlobalValue *GV, StringRef Name) {
// If the global doesn't force its name or if it already has the right name,
// there is nothing for us to do.
if (GV->hasLocalLinkage() || GV->getName() == Name)
return;
Module *M = GV->getParent();
// If there is a conflict, rename the conflict.
if (GlobalValue *ConflictGV = M->getNamedValue(Name)) {
GV->takeName(ConflictGV);
ConflictGV->setName(Name); // This will cause ConflictGV to get renamed
assert(ConflictGV->getName() != Name && "forceRenaming didn't work");
} else {
GV->setName(Name); // Force the name back
}
}
/// copyGVAttributes - copy additional attributes (those not needed to construct
/// a GlobalValue) from the SrcGV to the DestGV.
static void copyGVAttributes(GlobalValue *DestGV, const GlobalValue *SrcGV) {
// Use the maximum alignment, rather than just copying the alignment of SrcGV.
unsigned Alignment = std::max(DestGV->getAlignment(), SrcGV->getAlignment());
DestGV->copyAttributesFrom(SrcGV);
DestGV->setAlignment(Alignment);
forceRenaming(DestGV, SrcGV->getName());
}
static bool isLessConstraining(GlobalValue::VisibilityTypes a,
GlobalValue::VisibilityTypes b) {
if (a == GlobalValue::HiddenVisibility)
return false;
if (b == GlobalValue::HiddenVisibility)
return true;
if (a == GlobalValue::ProtectedVisibility)
return false;
if (b == GlobalValue::ProtectedVisibility)
return true;
return false;
}
/// getLinkageResult - This analyzes the two global values and determines what
/// the result will look like in the destination module. In particular, it
/// computes the resultant linkage type and visibility, computes whether the
/// global in the source should be copied over to the destination (replacing
/// the existing one), and computes whether this linkage is an error or not.
bool ModuleLinker::getLinkageResult(GlobalValue *Dest, const GlobalValue *Src,
GlobalValue::LinkageTypes &LT,
GlobalValue::VisibilityTypes &Vis,
bool &LinkFromSrc) {
assert(Dest && "Must have two globals being queried");
assert(!Src->hasLocalLinkage() &&
"If Src has internal linkage, Dest shouldn't be set!");
bool SrcIsDeclaration = Src->isDeclaration() && !Src->isMaterializable();
bool DestIsDeclaration = Dest->isDeclaration();
if (SrcIsDeclaration) {
// If Src is external or if both Src & Dest are external.. Just link the
// external globals, we aren't adding anything.
if (Src->hasDLLImportLinkage()) {
// If one of GVs has DLLImport linkage, result should be dllimport'ed.
if (DestIsDeclaration) {
LinkFromSrc = true;
LT = Src->getLinkage();
}
} else if (Dest->hasExternalWeakLinkage()) {
// If the Dest is weak, use the source linkage.
LinkFromSrc = true;
LT = Src->getLinkage();
} else {
LinkFromSrc = false;
LT = Dest->getLinkage();
}
} else if (DestIsDeclaration && !Dest->hasDLLImportLinkage()) {
// If Dest is external but Src is not:
LinkFromSrc = true;
LT = Src->getLinkage();
} else if (Src->isWeakForLinker()) {
// At this point we know that Dest has LinkOnce, External*, Weak, Common,
// or DLL* linkage.
if (Dest->hasExternalWeakLinkage() ||
Dest->hasAvailableExternallyLinkage() ||
(Dest->hasLinkOnceLinkage() &&
(Src->hasWeakLinkage() || Src->hasCommonLinkage()))) {
LinkFromSrc = true;
LT = Src->getLinkage();
} else {
LinkFromSrc = false;
LT = Dest->getLinkage();
}
} else if (Dest->isWeakForLinker()) {
// At this point we know that Src has External* or DLL* linkage.
if (Src->hasExternalWeakLinkage()) {
LinkFromSrc = false;
LT = Dest->getLinkage();
} else {
LinkFromSrc = true;
LT = GlobalValue::ExternalLinkage;
}
} else {
assert((Dest->hasExternalLinkage() || Dest->hasDLLImportLinkage() ||
Dest->hasDLLExportLinkage() || Dest->hasExternalWeakLinkage()) &&
(Src->hasExternalLinkage() || Src->hasDLLImportLinkage() ||
Src->hasDLLExportLinkage() || Src->hasExternalWeakLinkage()) &&
"Unexpected linkage type!");
return emitError("Linking globals named '" + Src->getName() +
"': symbol multiply defined!");
}
// Compute the visibility. We follow the rules in the System V Application
// Binary Interface.
Vis = isLessConstraining(Src->getVisibility(), Dest->getVisibility()) ?
Dest->getVisibility() : Src->getVisibility();
return false;
}
/// computeTypeMapping - Loop over all of the linked values to compute type
/// mappings. For example, if we link "extern Foo *x" and "Foo *x = NULL", then
/// we have two struct types 'Foo' but one got renamed when the module was
/// loaded into the same LLVMContext.
void ModuleLinker::computeTypeMapping() {
// Incorporate globals.
for (Module::global_iterator I = SrcM->global_begin(),
E = SrcM->global_end(); I != E; ++I) {
GlobalValue *DGV = getLinkedToGlobal(I);
if (DGV == 0) continue;
if (!DGV->hasAppendingLinkage() || !I->hasAppendingLinkage()) {
TypeMap.addTypeMapping(DGV->getType(), I->getType());
continue;
}
// Unify the element type of appending arrays.
ArrayType *DAT = cast<ArrayType>(DGV->getType()->getElementType());
ArrayType *SAT = cast<ArrayType>(I->getType()->getElementType());
TypeMap.addTypeMapping(DAT->getElementType(), SAT->getElementType());
}
// Incorporate functions.
for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I) {
if (GlobalValue *DGV = getLinkedToGlobal(I))
TypeMap.addTypeMapping(DGV->getType(), I->getType());
}
// Incorporate types by name, scanning all the types in the source module.
// At this point, the destination module may have a type "%foo = { i32 }" for
// example. When the source module got loaded into the same LLVMContext, if
// it had the same type, it would have been renamed to "%foo.42 = { i32 }".
std::vector<StructType*> SrcStructTypes;
SrcM->findUsedStructTypes(SrcStructTypes);
SmallPtrSet<StructType*, 32> SrcStructTypesSet(SrcStructTypes.begin(),
SrcStructTypes.end());
std::vector<StructType*> DstStructTypes;
DstM->findUsedStructTypes(DstStructTypes);
SmallPtrSet<StructType*, 32> DstStructTypesSet(DstStructTypes.begin(),
DstStructTypes.end());
for (unsigned i = 0, e = SrcStructTypes.size(); i != e; ++i) {
StructType *ST = SrcStructTypes[i];
if (!ST->hasName()) continue;
// Check to see if there is a dot in the name followed by a digit.
size_t DotPos = ST->getName().rfind('.');
if (DotPos == 0 || DotPos == StringRef::npos ||
ST->getName().back() == '.' || !isdigit(ST->getName()[DotPos+1]))
continue;
// Check to see if the destination module has a struct with the prefix name.
if (StructType *DST = DstM->getTypeByName(ST->getName().substr(0, DotPos)))
// Don't use it if this actually came from the source module. They're in
// the same LLVMContext after all. Also don't use it unless the type is
// actually used in the destination module. This can happen in situations
// like this:
//
// Module A Module B
// -------- --------
// %Z = type { %A } %B = type { %C.1 }
// %A = type { %B.1, [7 x i8] } %C.1 = type { i8* }
// %B.1 = type { %C } %A.2 = type { %B.3, [5 x i8] }
// %C = type { i8* } %B.3 = type { %C.1 }
//
// When we link Module B with Module A, the '%B' in Module B is
// used. However, that would then use '%C.1'. But when we process '%C.1',
// we prefer to take the '%C' version. So we are then left with both
// '%C.1' and '%C' being used for the same types. This leads to some
// variables using one type and some using the other.
if (!SrcStructTypesSet.count(DST) && DstStructTypesSet.count(DST))
TypeMap.addTypeMapping(DST, ST);
}
// Don't bother incorporating aliases, they aren't generally typed well.
// Now that we have discovered all of the type equivalences, get a body for
// any 'opaque' types in the dest module that are now resolved.
TypeMap.linkDefinedTypeBodies();
}
/// linkAppendingVarProto - If there were any appending global variables, link
/// them together now. Return true on error.
bool ModuleLinker::linkAppendingVarProto(GlobalVariable *DstGV,
GlobalVariable *SrcGV) {
if (!SrcGV->hasAppendingLinkage() || !DstGV->hasAppendingLinkage())
return emitError("Linking globals named '" + SrcGV->getName() +
"': can only link appending global with another appending global!");
ArrayType *DstTy = cast<ArrayType>(DstGV->getType()->getElementType());
ArrayType *SrcTy =
cast<ArrayType>(TypeMap.get(SrcGV->getType()->getElementType()));
Type *EltTy = DstTy->getElementType();
// Check to see that they two arrays agree on type.
if (EltTy != SrcTy->getElementType())
return emitError("Appending variables with different element types!");
if (DstGV->isConstant() != SrcGV->isConstant())
return emitError("Appending variables linked with different const'ness!");
if (DstGV->getAlignment() != SrcGV->getAlignment())
return emitError(
"Appending variables with different alignment need to be linked!");
if (DstGV->getVisibility() != SrcGV->getVisibility())
return emitError(
"Appending variables with different visibility need to be linked!");
if (DstGV->getSection() != SrcGV->getSection())
return emitError(
"Appending variables with different section name need to be linked!");
uint64_t NewSize = DstTy->getNumElements() + SrcTy->getNumElements();
ArrayType *NewType = ArrayType::get(EltTy, NewSize);
// Create the new global variable.
GlobalVariable *NG =
new GlobalVariable(*DstGV->getParent(), NewType, SrcGV->isConstant(),
DstGV->getLinkage(), /*init*/0, /*name*/"", DstGV,
DstGV->isThreadLocal(),
DstGV->getType()->getAddressSpace());
// Propagate alignment, visibility and section info.
copyGVAttributes(NG, DstGV);
AppendingVarInfo AVI;
AVI.NewGV = NG;
AVI.DstInit = DstGV->getInitializer();
AVI.SrcInit = SrcGV->getInitializer();
AppendingVars.push_back(AVI);
// Replace any uses of the two global variables with uses of the new
// global.
ValueMap[SrcGV] = ConstantExpr::getBitCast(NG, TypeMap.get(SrcGV->getType()));
DstGV->replaceAllUsesWith(ConstantExpr::getBitCast(NG, DstGV->getType()));
DstGV->eraseFromParent();
// Track the source variable so we don't try to link it.
DoNotLinkFromSource.insert(SrcGV);
return false;
}
/// linkGlobalProto - Loop through the global variables in the src module and
/// merge them into the dest module.
bool ModuleLinker::linkGlobalProto(GlobalVariable *SGV) {
GlobalValue *DGV = getLinkedToGlobal(SGV);
llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
if (DGV) {
// Concatenation of appending linkage variables is magic and handled later.
if (DGV->hasAppendingLinkage() || SGV->hasAppendingLinkage())
return linkAppendingVarProto(cast<GlobalVariable>(DGV), SGV);
// Determine whether linkage of these two globals follows the source
// module's definition or the destination module's definition.
GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
GlobalValue::VisibilityTypes NV;
bool LinkFromSrc = false;
if (getLinkageResult(DGV, SGV, NewLinkage, NV, LinkFromSrc))
return true;
NewVisibility = NV;
// If we're not linking from the source, then keep the definition that we
// have.
if (!LinkFromSrc) {
// Special case for const propagation.
if (GlobalVariable *DGVar = dyn_cast<GlobalVariable>(DGV))
if (DGVar->isDeclaration() && SGV->isConstant() && !DGVar->isConstant())
DGVar->setConstant(true);
// Set calculated linkage and visibility.
DGV->setLinkage(NewLinkage);
DGV->setVisibility(*NewVisibility);
// Make sure to remember this mapping.
ValueMap[SGV] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGV->getType()));
// Track the source global so that we don't attempt to copy it over when
// processing global initializers.
DoNotLinkFromSource.insert(SGV);
return false;
}
}
// No linking to be performed or linking from the source: simply create an
// identical version of the symbol over in the dest module... the
// initializer will be filled in later by LinkGlobalInits.
GlobalVariable *NewDGV =
new GlobalVariable(*DstM, TypeMap.get(SGV->getType()->getElementType()),
SGV->isConstant(), SGV->getLinkage(), /*init*/0,
SGV->getName(), /*insertbefore*/0,
SGV->isThreadLocal(),
SGV->getType()->getAddressSpace());
// Propagate alignment, visibility and section info.
copyGVAttributes(NewDGV, SGV);
if (NewVisibility)
NewDGV->setVisibility(*NewVisibility);
if (DGV) {
DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDGV, DGV->getType()));
DGV->eraseFromParent();
}
// Make sure to remember this mapping.
ValueMap[SGV] = NewDGV;
return false;
}
/// linkFunctionProto - Link the function in the source module into the
/// destination module if needed, setting up mapping information.
bool ModuleLinker::linkFunctionProto(Function *SF) {
GlobalValue *DGV = getLinkedToGlobal(SF);
llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
if (DGV) {
GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
bool LinkFromSrc = false;
GlobalValue::VisibilityTypes NV;
if (getLinkageResult(DGV, SF, NewLinkage, NV, LinkFromSrc))
return true;
NewVisibility = NV;
if (!LinkFromSrc) {
// Set calculated linkage
DGV->setLinkage(NewLinkage);
DGV->setVisibility(*NewVisibility);
// Make sure to remember this mapping.
ValueMap[SF] = ConstantExpr::getBitCast(DGV, TypeMap.get(SF->getType()));
// Track the function from the source module so we don't attempt to remap
// it.
DoNotLinkFromSource.insert(SF);
return false;
}
}
// If there is no linkage to be performed or we are linking from the source,
// bring SF over.
Function *NewDF = Function::Create(TypeMap.get(SF->getFunctionType()),
SF->getLinkage(), SF->getName(), DstM);
copyGVAttributes(NewDF, SF);
if (NewVisibility)
NewDF->setVisibility(*NewVisibility);
if (DGV) {
// Any uses of DF need to change to NewDF, with cast.
DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDF, DGV->getType()));
DGV->eraseFromParent();
} else {
// Internal, LO_ODR, or LO linkage - stick in set to ignore and lazily link.
if (SF->hasLocalLinkage() || SF->hasLinkOnceLinkage() ||
SF->hasAvailableExternallyLinkage()) {
DoNotLinkFromSource.insert(SF);
LazilyLinkFunctions.push_back(SF);
}
}
ValueMap[SF] = NewDF;
return false;
}
/// LinkAliasProto - Set up prototypes for any aliases that come over from the
/// source module.
bool ModuleLinker::linkAliasProto(GlobalAlias *SGA) {
GlobalValue *DGV = getLinkedToGlobal(SGA);
llvm::Optional<GlobalValue::VisibilityTypes> NewVisibility;
if (DGV) {
GlobalValue::LinkageTypes NewLinkage = GlobalValue::InternalLinkage;
GlobalValue::VisibilityTypes NV;
bool LinkFromSrc = false;
if (getLinkageResult(DGV, SGA, NewLinkage, NV, LinkFromSrc))
return true;
NewVisibility = NV;
if (!LinkFromSrc) {
// Set calculated linkage.
DGV->setLinkage(NewLinkage);
DGV->setVisibility(*NewVisibility);
// Make sure to remember this mapping.
ValueMap[SGA] = ConstantExpr::getBitCast(DGV,TypeMap.get(SGA->getType()));
// Track the alias from the source module so we don't attempt to remap it.
DoNotLinkFromSource.insert(SGA);
return false;
}
}
// If there is no linkage to be performed or we're linking from the source,
// bring over SGA.
GlobalAlias *NewDA = new GlobalAlias(TypeMap.get(SGA->getType()),
SGA->getLinkage(), SGA->getName(),
/*aliasee*/0, DstM);
copyGVAttributes(NewDA, SGA);
if (NewVisibility)
NewDA->setVisibility(*NewVisibility);
if (DGV) {
// Any uses of DGV need to change to NewDA, with cast.
DGV->replaceAllUsesWith(ConstantExpr::getBitCast(NewDA, DGV->getType()));
DGV->eraseFromParent();
}
ValueMap[SGA] = NewDA;
return false;
}
static void getArrayElements(Constant *C, SmallVectorImpl<Constant*> &Dest) {
unsigned NumElements = cast<ArrayType>(C->getType())->getNumElements();
for (unsigned i = 0; i != NumElements; ++i)
Dest.push_back(C->getAggregateElement(i));
}
void ModuleLinker::linkAppendingVarInit(const AppendingVarInfo &AVI) {
// Merge the initializer.
SmallVector<Constant*, 16> Elements;
getArrayElements(AVI.DstInit, Elements);
Constant *SrcInit = MapValue(AVI.SrcInit, ValueMap, RF_None, &TypeMap);
getArrayElements(SrcInit, Elements);
ArrayType *NewType = cast<ArrayType>(AVI.NewGV->getType()->getElementType());
AVI.NewGV->setInitializer(ConstantArray::get(NewType, Elements));
}
/// linkGlobalInits - Update the initializers in the Dest module now that all
/// globals that may be referenced are in Dest.
void ModuleLinker::linkGlobalInits() {
// Loop over all of the globals in the src module, mapping them over as we go
for (Module::const_global_iterator I = SrcM->global_begin(),
E = SrcM->global_end(); I != E; ++I) {
// Only process initialized GV's or ones not already in dest.
if (!I->hasInitializer() || DoNotLinkFromSource.count(I)) continue;
// Grab destination global variable.
GlobalVariable *DGV = cast<GlobalVariable>(ValueMap[I]);
// Figure out what the initializer looks like in the dest module.
DGV->setInitializer(MapValue(I->getInitializer(), ValueMap,
RF_None, &TypeMap));
}
}
/// linkFunctionBody - Copy the source function over into the dest function and
/// fix up references to values. At this point we know that Dest is an external
/// function, and that Src is not.
void ModuleLinker::linkFunctionBody(Function *Dst, Function *Src) {
assert(Src && Dst && Dst->isDeclaration() && !Src->isDeclaration());
// Go through and convert function arguments over, remembering the mapping.
Function::arg_iterator DI = Dst->arg_begin();
for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
I != E; ++I, ++DI) {
DI->setName(I->getName()); // Copy the name over.
// Add a mapping to our mapping.
ValueMap[I] = DI;
}
if (Mode == Linker::DestroySource) {
// Splice the body of the source function into the dest function.
Dst->getBasicBlockList().splice(Dst->end(), Src->getBasicBlockList());
// At this point, all of the instructions and values of the function are now
// copied over. The only problem is that they are still referencing values in
// the Source function as operands. Loop through all of the operands of the
// functions and patch them up to point to the local versions.
for (Function::iterator BB = Dst->begin(), BE = Dst->end(); BB != BE; ++BB)
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
RemapInstruction(I, ValueMap, RF_IgnoreMissingEntries, &TypeMap);
} else {
// Clone the body of the function into the dest function.
SmallVector<ReturnInst*, 8> Returns; // Ignore returns.
CloneFunctionInto(Dst, Src, ValueMap, false, Returns, "", NULL, &TypeMap);
}
// There is no need to map the arguments anymore.
for (Function::arg_iterator I = Src->arg_begin(), E = Src->arg_end();
I != E; ++I)
ValueMap.erase(I);
}
/// linkAliasBodies - Insert all of the aliases in Src into the Dest module.
void ModuleLinker::linkAliasBodies() {
for (Module::alias_iterator I = SrcM->alias_begin(), E = SrcM->alias_end();
I != E; ++I) {
if (DoNotLinkFromSource.count(I))
continue;
if (Constant *Aliasee = I->getAliasee()) {
GlobalAlias *DA = cast<GlobalAlias>(ValueMap[I]);
DA->setAliasee(MapValue(Aliasee, ValueMap, RF_None, &TypeMap));
}
}
}
/// linkNamedMDNodes - Insert all of the named MDNodes in Src into the Dest
/// module.
void ModuleLinker::linkNamedMDNodes() {
const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
for (Module::const_named_metadata_iterator I = SrcM->named_metadata_begin(),
E = SrcM->named_metadata_end(); I != E; ++I) {
// Don't link module flags here. Do them separately.
if (&*I == SrcModFlags) continue;
NamedMDNode *DestNMD = DstM->getOrInsertNamedMetadata(I->getName());
// Add Src elements into Dest node.
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
DestNMD->addOperand(MapValue(I->getOperand(i), ValueMap,
RF_None, &TypeMap));
}
}
/// categorizeModuleFlagNodes - Categorize the module flags according to their
/// type: Error, Warning, Override, and Require.
bool ModuleLinker::
categorizeModuleFlagNodes(const NamedMDNode *ModFlags,
DenseMap<MDString*, MDNode*> &ErrorNode,
DenseMap<MDString*, MDNode*> &WarningNode,
DenseMap<MDString*, MDNode*> &OverrideNode,
DenseMap<MDString*,
SmallSetVector<MDNode*, 8> > &RequireNodes,
SmallSetVector<MDString*, 16> &SeenIDs) {
bool HasErr = false;
for (unsigned I = 0, E = ModFlags->getNumOperands(); I != E; ++I) {
MDNode *Op = ModFlags->getOperand(I);
assert(Op->getNumOperands() == 3 && "Invalid module flag metadata!");
assert(isa<ConstantInt>(Op->getOperand(0)) &&
"Module flag's first operand must be an integer!");
assert(isa<MDString>(Op->getOperand(1)) &&
"Module flag's second operand must be an MDString!");
ConstantInt *Behavior = cast<ConstantInt>(Op->getOperand(0));
MDString *ID = cast<MDString>(Op->getOperand(1));
Value *Val = Op->getOperand(2);
switch (Behavior->getZExtValue()) {
default:
assert(false && "Invalid behavior in module flag metadata!");
break;
case Module::Error: {
MDNode *&ErrNode = ErrorNode[ID];
if (!ErrNode) ErrNode = Op;
if (ErrNode->getOperand(2) != Val)
HasErr = emitError("linking module flags '" + ID->getString() +
"': IDs have conflicting values");
break;
}
case Module::Warning: {
MDNode *&WarnNode = WarningNode[ID];
if (!WarnNode) WarnNode = Op;
if (WarnNode->getOperand(2) != Val)
errs() << "WARNING: linking module flags '" << ID->getString()
<< "': IDs have conflicting values";
break;
}
case Module::Require: RequireNodes[ID].insert(Op); break;
case Module::Override: {
MDNode *&OvrNode = OverrideNode[ID];
if (!OvrNode) OvrNode = Op;
if (OvrNode->getOperand(2) != Val)
HasErr = emitError("linking module flags '" + ID->getString() +
"': IDs have conflicting override values");
break;
}
}
SeenIDs.insert(ID);
}
return HasErr;
}
/// linkModuleFlagsMetadata - Merge the linker flags in Src into the Dest
/// module.
bool ModuleLinker::linkModuleFlagsMetadata() {
const NamedMDNode *SrcModFlags = SrcM->getModuleFlagsMetadata();
if (!SrcModFlags) return false;
NamedMDNode *DstModFlags = DstM->getOrInsertModuleFlagsMetadata();
// If the destination module doesn't have module flags yet, then just copy
// over the source module's flags.
if (DstModFlags->getNumOperands() == 0) {
for (unsigned I = 0, E = SrcModFlags->getNumOperands(); I != E; ++I)
DstModFlags->addOperand(SrcModFlags->getOperand(I));
return false;
}
bool HasErr = false;
// Otherwise, we have to merge them based on their behaviors. First,
// categorize all of the nodes in the modules' module flags. If an error or
// warning occurs, then emit the appropriate message(s).
DenseMap<MDString*, MDNode*> ErrorNode;
DenseMap<MDString*, MDNode*> WarningNode;
DenseMap<MDString*, MDNode*> OverrideNode;
DenseMap<MDString*, SmallSetVector<MDNode*, 8> > RequireNodes;
SmallSetVector<MDString*, 16> SeenIDs;
HasErr |= categorizeModuleFlagNodes(SrcModFlags, ErrorNode, WarningNode,
OverrideNode, RequireNodes, SeenIDs);
HasErr |= categorizeModuleFlagNodes(DstModFlags, ErrorNode, WarningNode,
OverrideNode, RequireNodes, SeenIDs);
// Check that there isn't both an error and warning node for a flag.
for (SmallSetVector<MDString*, 16>::iterator
I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) {
MDString *ID = *I;
if (ErrorNode[ID] && WarningNode[ID])
HasErr = emitError("linking module flags '" + ID->getString() +
"': IDs have conflicting behaviors");
}
// Early exit if we had an error.
if (HasErr) return true;
// Get the destination's module flags ready for new operands.
DstModFlags->dropAllReferences();
// Add all of the module flags to the destination module.
DenseMap<MDString*, SmallVector<MDNode*, 4> > AddedNodes;
for (SmallSetVector<MDString*, 16>::iterator
I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) {
MDString *ID = *I;
if (OverrideNode[ID]) {
DstModFlags->addOperand(OverrideNode[ID]);
AddedNodes[ID].push_back(OverrideNode[ID]);
} else if (ErrorNode[ID]) {
DstModFlags->addOperand(ErrorNode[ID]);
AddedNodes[ID].push_back(ErrorNode[ID]);
} else if (WarningNode[ID]) {
DstModFlags->addOperand(WarningNode[ID]);
AddedNodes[ID].push_back(WarningNode[ID]);
}
for (SmallSetVector<MDNode*, 8>::iterator
II = RequireNodes[ID].begin(), IE = RequireNodes[ID].end();
II != IE; ++II)
DstModFlags->addOperand(*II);
}
// Now check that all of the requirements have been satisfied.
for (SmallSetVector<MDString*, 16>::iterator
I = SeenIDs.begin(), E = SeenIDs.end(); I != E; ++I) {
MDString *ID = *I;
SmallSetVector<MDNode*, 8> &Set = RequireNodes[ID];
for (SmallSetVector<MDNode*, 8>::iterator
II = Set.begin(), IE = Set.end(); II != IE; ++II) {
MDNode *Node = *II;
assert(isa<MDNode>(Node->getOperand(2)) &&
"Module flag's third operand must be an MDNode!");
MDNode *Val = cast<MDNode>(Node->getOperand(2));
MDString *ReqID = cast<MDString>(Val->getOperand(0));
Value *ReqVal = Val->getOperand(1);
bool HasValue = false;
for (SmallVectorImpl<MDNode*>::iterator
RI = AddedNodes[ReqID].begin(), RE = AddedNodes[ReqID].end();
RI != RE; ++RI) {
MDNode *ReqNode = *RI;
if (ReqNode->getOperand(2) == ReqVal) {
HasValue = true;
break;
}
}
if (!HasValue)
HasErr = emitError("linking module flags '" + ReqID->getString() +
"': does not have the required value");
}
}
return HasErr;
}
bool ModuleLinker::run() {
assert(DstM && "Null destination module");
assert(SrcM && "Null source module");
// Inherit the target data from the source module if the destination module
// doesn't have one already.
if (DstM->getDataLayout().empty() && !SrcM->getDataLayout().empty())
DstM->setDataLayout(SrcM->getDataLayout());
// Copy the target triple from the source to dest if the dest's is empty.
if (DstM->getTargetTriple().empty() && !SrcM->getTargetTriple().empty())
DstM->setTargetTriple(SrcM->getTargetTriple());
if (!SrcM->getDataLayout().empty() && !DstM->getDataLayout().empty() &&
SrcM->getDataLayout() != DstM->getDataLayout())
errs() << "WARNING: Linking two modules of different data layouts!\n";
if (!SrcM->getTargetTriple().empty() &&
DstM->getTargetTriple() != SrcM->getTargetTriple()) {
errs() << "WARNING: Linking two modules of different target triples: ";
if (!SrcM->getModuleIdentifier().empty())
errs() << SrcM->getModuleIdentifier() << ": ";
errs() << "'" << SrcM->getTargetTriple() << "' and '"
<< DstM->getTargetTriple() << "'\n";
}
// Append the module inline asm string.
if (!SrcM->getModuleInlineAsm().empty()) {
if (DstM->getModuleInlineAsm().empty())
DstM->setModuleInlineAsm(SrcM->getModuleInlineAsm());
else
DstM->setModuleInlineAsm(DstM->getModuleInlineAsm()+"\n"+
SrcM->getModuleInlineAsm());
}
// Update the destination module's dependent libraries list with the libraries
// from the source module. There's no opportunity for duplicates here as the
// Module ensures that duplicate insertions are discarded.
for (Module::lib_iterator SI = SrcM->lib_begin(), SE = SrcM->lib_end();
SI != SE; ++SI)
DstM->addLibrary(*SI);
// If the source library's module id is in the dependent library list of the
// destination library, remove it since that module is now linked in.
StringRef ModuleId = SrcM->getModuleIdentifier();
if (!ModuleId.empty())
DstM->removeLibrary(sys::path::stem(ModuleId));
// Loop over all of the linked values to compute type mappings.
computeTypeMapping();
// Insert all of the globals in src into the DstM module... without linking
// initializers (which could refer to functions not yet mapped over).
for (Module::global_iterator I = SrcM->global_begin(),
E = SrcM->global_end(); I != E; ++I)
if (linkGlobalProto(I))
return true;
// Link the functions together between the two modules, without doing function
// bodies... this just adds external function prototypes to the DstM
// function... We do this so that when we begin processing function bodies,
// all of the global values that may be referenced are available in our
// ValueMap.
for (Module::iterator I = SrcM->begin(), E = SrcM->end(); I != E; ++I)
if (linkFunctionProto(I))
return true;
// If there were any aliases, link them now.
for (Module::alias_iterator I = SrcM->alias_begin(),
E = SrcM->alias_end(); I != E; ++I)
if (linkAliasProto(I))
return true;
for (unsigned i = 0, e = AppendingVars.size(); i != e; ++i)
linkAppendingVarInit(AppendingVars[i]);
// Update the initializers in the DstM module now that all globals that may
// be referenced are in DstM.
linkGlobalInits();
// Link in the function bodies that are defined in the source module into
// DstM.
for (Module::iterator SF = SrcM->begin(), E = SrcM->end(); SF != E; ++SF) {
// Skip if not linking from source.
if (DoNotLinkFromSource.count(SF)) continue;
// Skip if no body (function is external) or materialize.
if (SF->isDeclaration()) {
if (!SF->isMaterializable())
continue;
if (SF->Materialize(&ErrorMsg))
return true;
}
linkFunctionBody(cast<Function>(ValueMap[SF]), SF);
SF->Dematerialize();
}
// Resolve all uses of aliases with aliasees.
linkAliasBodies();
// Remap all of the named MDNodes in Src into the DstM module. We do this
// after linking GlobalValues so that MDNodes that reference GlobalValues
// are properly remapped.
linkNamedMDNodes();
// Merge the module flags into the DstM module.
if (linkModuleFlagsMetadata())
return true;
// Process vector of lazily linked in functions.
bool LinkedInAnyFunctions;
do {
LinkedInAnyFunctions = false;
for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(),
E = LazilyLinkFunctions.end(); I != E; ++I) {
if (!*I)
continue;
Function *SF = *I;
Function *DF = cast<Function>(ValueMap[SF]);
if (!DF->use_empty()) {
// Materialize if necessary.
if (SF->isDeclaration()) {
if (!SF->isMaterializable())
continue;
if (SF->Materialize(&ErrorMsg))
return true;
}
// Link in function body.
linkFunctionBody(DF, SF);
SF->Dematerialize();
// "Remove" from vector by setting the element to 0.
*I = 0;
// Set flag to indicate we may have more functions to lazily link in
// since we linked in a function.
LinkedInAnyFunctions = true;
}
}
} while (LinkedInAnyFunctions);
// Remove any prototypes of functions that were not actually linked in.
for(std::vector<Function*>::iterator I = LazilyLinkFunctions.begin(),
E = LazilyLinkFunctions.end(); I != E; ++I) {
if (!*I)
continue;
Function *SF = *I;
Function *DF = cast<Function>(ValueMap[SF]);
if (DF->use_empty())
DF->eraseFromParent();
}
// Now that all of the types from the source are used, resolve any structs
// copied over to the dest that didn't exist there.
TypeMap.linkDefinedTypeBodies();
return false;
}
//===----------------------------------------------------------------------===//
// LinkModules entrypoint.
//===----------------------------------------------------------------------===//
/// LinkModules - This function links two modules together, with the resulting
/// left module modified to be the composite of the two input modules. If an
/// error occurs, true is returned and ErrorMsg (if not null) is set to indicate
/// the problem. Upon failure, the Dest module could be in a modified state,
/// and shouldn't be relied on to be consistent.
bool Linker::LinkModules(Module *Dest, Module *Src, unsigned Mode,
std::string *ErrorMsg) {
ModuleLinker TheLinker(Dest, Src, Mode);
if (TheLinker.run()) {
if (ErrorMsg) *ErrorMsg = TheLinker.ErrorMsg;
return true;
}
return false;
}
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